People have been watching the sky since times out of mind. In its broadest sense, one could compare the sky with a big screen that shows a film with a plot that’s hard to follow. Next to an infinite plenitude of sparkling lights, a flash would appear on the screen now and again, as if someone was trying to ignite a candle and failing. People would think the sky was inhabited by Gods who tended to the night-time illumination.

As time went by, people invented gadgets called ‘telescopes’ that helped them to get closer to the sky and give reading the book of heaven another try. The telescope is a gadget used to observe heavenly bodies and phenomena. Telescopes most often are optical devices, although they are evolving continuously and are now able to observe the space both within and without the band of the visible spectrum, for instance, in the band of radio waves or infrared rays (IR). The first person to employ a telescope for the purposes of astronomy in 1610 was the Italian astronomer Galileo Galilei.

The advent of the telescope triggered significant changes in the way people understood the sky. Apparently, the lights in the sky are other distant suns (stars), extra-terrestrial worlds. The ‘failed attempts to light a candle’ are meteors (residues of comet trails) that enter Earth’s atmosphere at speeds of 15 to 70 kilometres per second (as Earth rotates around the Sun) and burn out immediately from friction with the atmosphere, without even reaching the surface of Earth, since they actually weigh very little (roughly between 1 and 30 grams). The ‘long-burning candles’ are comets that cruise the edge of the solar system in elliptic orbits that stretch around the Sun. The closer a comet gets to the Sun, the more it melts and the higher its trail becomes, visible against the rays of the Sun. The trail of a comet can sometimes be longer than the radius of the Jupiter, which exceeds that of Earth a whopping 11 times.

The telescope changed people’s understanding of how the solar system as we know it was born and evolved. At a glance, it would appear serene and settled, however recent discoveries and research has showed the solar system to have had many milestones, evolutionary slaps in the face and extraordinary situations. People use the telescope both to find out more about the history of our solar system and to analyse other distant systems that right now are just being born.

The first telescopes

The first telescopes were very simple in structure, consisting of a few lenses and a tube.

In the long run, the telescope has evolved significantly:

In modern times, a telescope can be more than just one intricate gadget weighing many tons, but rather a system of them integrated to form a single network.

To minimise the unwelcome level of noise emitted by Earth’s atmosphere, telescopes are set up high in the mountains or deployed in space.

If you look up information about new telescope inventions, you will see that telescope patent applications alone have been more than 5,000 (currently, their number stands at a massive 5,725). And even though the telescope was invented ages ago, it has been undergoing continuous improvement and is now going through what may be referred to a kind of a ‘golden’ age, with the last few decades seeing great many developments driving the telescope – both the gadget itself, and the measuring techniques allowing to rediscover what used to be invisible or incomprehensible – to evolve further.

Even though the telescope has been undergoing constant development, we were only able to watch the planets of our solar system for a long time. All that we could see beyond the solar system were just centres (or conditional centres) of other systems where stars were localised (that is, they were Sun-type objects from other planetary systems). Also, a tiny shining object in the sky could be a star or an entire galaxy. It was only in 1992 that the first planet, Alpha Centauri, was discovered in a next-door system outside of the solar system, the distance between Alpha Centauri and the solar system measuring 4.39 lightyears. Despite the fact that the newly discovered planet is huge (bigger than Jupiter), it was the first step in the hunt for alien planets.

That is why the hunt for and analysis of alien planets only began in 2005, with the advent of new telescopes and new techniques. Technology that is available right now and will be developed in the future, covering both new telescopes and new recognition and calculation techniques, will enable people to estimate the size, mass of alien planets, the distance to a local star, calculate the orbit of the plant, determine the altitude and composition of its atmosphere, look for signs of water and life in the atmospheres of planets, measure the structure and temperature of a planet. All this is due to happen by the year 2025. Of course, the hunt for planetary systems has been going on in earnest already, with over 3,500 new planets discovered by early 2017. Every one of them is being gradually documented at length (both using modern technology and what will become available in future). As distances to alien planets differ many times from what we have in our solar system, we need increasingly better mathematical techniques and equipment. A preliminary analysis of the alien planets discovered (the information available right now) suggests that alien planets are so diverse and surprising that they do not fit in our contemporary models and understanding, because we live in the solar system and want to measure everything by our system’s ratios. Planets in other systems are a lot different from our own: there are planets that consist purely of water (one would find it difficult to imagine never-ending oceans thousands of kilometres deep, the water boiling to a depth of several metres on the side of the planet facing the star). There are also glacial giants (planets 5 times the size of Earth). Then there are planets made entirely of diamond. There are also gas giants that greatly excel our Jupiter in size, and many others. Even weirder are the orbits of the planets, and their location within the systems, let alone that a system may have not just one, but several suns (in which case the planets move around a quasi-centre, which is constantly relocating). Gas giants have been observed to revolve very close local stars, which goes counter to our modern understanding, considering the solar system. Of the 3,500 planets discovered, there are 44 that have (at least on paper) suitable conditions for life to appear and evolve; attempts to analyse these planets thoroughly will begin in 2025, using the latest telescopes and techniques (the Advanced Technology Large-Aperture Space Telescope, or ATLAS, is scheduled for launch in 2025).

Every type of telescope (radio, X-ray, infrared ray, gamma radiation, high energy particle, and so on) is designed to look at the universe through its own ‘pair of glasses.’ The infrared ray (IR) telescope holds a special place among those, and Spitzer, which was launched under a NASA project in 2003, is a good case in point. A paradox, but it was only then, in 2003, that people first saw the universe the way it appears in the IR band. This wave band is unique in the way that it allows us to see objects hidden behind cosmic ‘clouds,’ meaning that it was only in 2003 that people were able to pull this curtain aside and peek at the universe for the first time. The project and the telescope have brought in so much new and unexpected information that instead the original plan of thirty months, the project ran full-tilt for nearly 6 years until the reserves of liquid helium required to cool the telescope down ran out. Ever since, the telescope has been operating in the so-called ‘warm mode,’ scanning the space in the 3.4 and 4.5 millimetre band.

The use of higher-precision telescopes and the processing of information that has been collected, a brand new model of the evolution of the solar system appeared in 2005: previously, scientists believed that the planets in our solar system have more or less stationary orbits, but it appeared not to be the case, resulting in another breakthrough. Apparently, the orbits of our planets are not stable and depend on the planetary interaction, changing constantly (at a higher or lower speed) and can shift beyond recognition in the long run. One of the mysteries is that Mars used to have an ocean of water (rather than ice), which has already been proven, but now it is only covered in rock and has a weak atmosphere (only amounting to 1 per cent of Earth’s atmosphere). It looks like Mars has been gradually drifting further and further away from the Sun, possibly due to the synchronised effect of Jupiter or Jupiter and Saturn. There is also a lot of uncertainty regarding Uranus and Neptune, because the orbits of these planets do not match the modern-day image at all. Therefore, the proven fact is that the planets first appeared in some original orbits, which then shifted radically over the course of time. Therefore, all planets interact, but sometimes, when the so-called planetary parades happen, irreversible processes can take place, with a planet shifting to a side so that it can no longer return to its old orbit. If our system had two planets the size of Jupiter, sooner or later they would push all other planets in the system outside the solar system. This almost happened in our system, too, for Jupiter and Saturn dangerous bedfellows make, but Saturn was a bit short on mass, and the planets moved further away from the interior space of the solar system, apparently casting Uranus and Neptune into orbits more remote.

State-of-the-art telescopes allow us to answer the questions that people were worrying over in the old days; but now we have even more new questions that are a cause for serious concern. We can see that the mankind has to make rapid progress, because if a meteor emerged from space today, the possibility of altering its trajectory or stopping it before it enters Earth’s atmosphere is virtually nil, because a meteorite can travel at speeds of up to 72 kilometres per second and we can only spot smaller (but nonetheless dangerous) meteorites but seconds from impact. To address this issue, there are some cautious theoretical solutions (one of the original options being detonating a nuclear bomb in the proximity of the meteorite, another, warming up one side of the meteorite with a laser to make it change its trajectory; yet another solution was to attach a solar sail to the meteorite to be able to steer it in advance if only for a little), but all these options only exist on paper and so far could not be brought to fruition. Experience shows that small meteorites can cause a lot of serious problems. Some (smaller) meteorites explode in the air before they reach the surface of Earth (such as the Tunguska incident), but even they can be a nuisance (a meteorite explosion over Chelyabinsk in 2013 left 1,000 injured; the meteorite was but 20 metres long and was only spotted hours before it entered our atmosphere). A meteorite hitting the surface of the Earth would result in an explosion would be comparable to a nuclear bomb blast, and ocean-based impact would cause a mega-tsunami; if the meteorite were several kilometres in girth, even the mountains of Tibet would likely fail to offer a safe shelter (the Biblical story of the flood most likely has a solid foundation and the makings of being true, relating to some minor meteorite falling into an Earth ocean).

Even though astronomers are watching and in their database have catalogued over 15,000 asteroids that are revolving close to Earth and are prone to cause damage, the catalogue is far from being complete. In 1992, the telescope helped them make yet another shocking discovery: the solar system does not end with Pluto (currently, Pluto is no longer regarded as a planet but rather a dwarf, because its radius is only about 68 per cent of that of the Moon). Beyond the orbit of Neptune, the so-called Kuiper belt begins, consisting of some 70,000 sizeable chunks of ice with several to 100 kilometres in diameter that, due to some external effect, could potentially bombard the interior section of the solar system. The Kuiper belt is quite far away and is difficult to observe from Earth. NASA’s new probe started making its way towards the region in 2006 and is currently still in transit.

Beyond the Kuiper belt, still 10 times (or roughly one lightyear) further away from Earth, there is the so-called Oort cloud with a large quantity of potential comets, counting in trillions. Any supernova exploding within the radius of 30 lightyears of the centre of our system would bring drastic changes to the Oort cloud with a commensurate aftermath.

And so, the telescope helps us understand our place in space better just as it allows us to predict and prepare to prevent future catastrophes. We know today that we live in a hive of comets beyond count, and what we will see gazing through our telescopes in future will only be limited by our own ingenuity, thirst for knowledge, and curiosity.